speaker design

Yes good grief, we don't live in the middle ages any more. When you buy a noise box at least make sure it can do the very basics Or rather - you have to consult the manual at some stage...

I bought a radio for my boat, can't believe this thing.

It's a radio, cd, DVD, USB, SD card and a TV all in one. Camera input too so you can see the back of the boat when you reverse. (or is that sail backwards ) Even has a synthesizer built in.

Has a small TFT diaplay, as well as a video output for a large display. I have an 11" and a 22" 12V display, will see which fits the best so I can clearly see what's going on. Looking for a GPS/chart plotter with a video output to connect to the camera video input while sailing.

Best of all, it has a volume control, balance and fader built in the stereo

Another radio in the same series even has a GPS built in. Didn't know about it or I'd have gotten that one instead.

 

Dont even have that at home fanie ... is that like a wounder box or something ? You missed cable though and can you hook it up to ur fish finder?

Auto volume control is always nice with higher speed volume goes up to compensate and better protection is always welcome.

 

My boat has like 10 rooms all connected to one sound system that can either play radio, cd, mp3, computer, tv, dvd, vhf. But what happens that I listening to radio in one room but them I get a phone call and can't just lower radio. I don't want to spend money for a system in every room or a fancy multi remote control system. I am sure I am not only person with this problem.

 

A friend of mine had a similar setup in his house, but each room had a volume control for that room only (it was a dial like switch like a dimmer).
So each room had its volume level.

 

Don't have at home either, it's for the boat. Don't have cleats in the home either...

That's called a ship and not a boat. If you insist on boat then it's a holtel. Solution is easy, the guests bring their own


You can install a line transformer thingy, each room's audio is 'independant' of the next.

Btw, who does the cooking for ten rooms

 

They're called potentiometers or "pots". A volume control. You can add one to every single speaker if you like.

-Tom

 

thx

 

NO !!! You cannot parrallel a bunch of speakers, pots or no pots. The impedance may go too low and short the audio out.

You need a line system, it works off a high voltage, each speaker tap has a high to low impedence tap, this way adding extra taps which has high impedance has little effect on the source.

 

fanie do you have access to any electric diagram for this setup ?

 

For most a circuit is not going to help. You need a public adress amplifier. Output audio line is typical 100V, and you get some that works off 12V, 24V, and or mains.

From the 100V audio line you tap to a line transformer that drives the speakers. The transformer has a hig impedence side and a low impedence side, the low side goes to the speaker.

This is the correct way to drive multiple speakers, otherwise, get more than one radio...

 

Fanie, do you think this simple scheme could work? The resistance R would be similar to the resistive part of speaker's impedance Z. The idea would be to by-pass each of the speakers in the system with a switch (S1, S2, S3...) without modifying the total impedance of the line.

 

Ok, the problem is the volume may not be set high enough to drive a bunch of speakers in series. A lot also depends on the quality output you expect from the speakers.

In that circuit I assume the resistor is to keep the impedance constant if a speaker is switched in or out. It will work, but you still cannot adjust the volume of each speaker... and certainly not 10 speakers for 10 rooms in your hotel I mean boat (good grief what boat do you have ?)

What could also work, and this is what I would do instead, is to obtain aditional audio amps to drive each speaker with. You need a 12W RMS audio output min for good audio levels (typical ~ 36W into 4R), won't rip your battery and the radio or source outputs drives into a low impedence. So if you have 10 x 100R resistors on each amp input you will have a constant 10R on the source output. Volume and tone control can be done on each of the aplifiers.

A simple audio amp could probably be obtained from any person out there that builds a bit of electronic stuff. Even DIY kits for such a thing should be available, check component suppliers.

 

Yes, right - it's not a volume control. It was meant to be a cheap add-on "mute" swich for individual speakers. See Mydauphin's problem in the post #18.
Thanks for the reply, cheers!

P.S.
However, Mydauphin - you have a boat with 10 rooms but don't want to spend few bucks for a decent sound system. Well, come on...

 

Something like this, the R's is close to the amp inputs to rule out induction problems

 

Whooops wrong picture

Try this one.